Social and economic deprivation impacts on rates of psychotic illness

December 14, 2012

Urban life is known to impact on rates of schizophrenia, however, until now, very little was known about the influential factors that led to this increased risk. A new study from the department elucidates some of the key determinants that lead to increased risk for psychotic illness in urban areas, highlighting the role of social and economic inequality.

Results of the two year study, led by Dr James Kirkbride, was published in Schizophrenia Bulletin today. In collaboration with Queen Mary University of London, the researchers investigated the sociospatial distribution of psychotic disorders in ethnically diverse and deprived boroughs of London.

Using a Bayesian model, the authors collected individual information for 427 people aged 18-64 who had experienced first-episode psychosis to estimate the incidence across 56 different neighbourhoods in City and Hackney, Newham, and Tower Hamlets. The research team also collected data on the urban environment in which the participants were living when they first presented with psychosis. Data were then standardised for age, sex, ethnicity, and socioeconomic status. Even taking account of these differences in demographics, incidence of psychotic illness, including schizophrenia, was found to differ between neighbourhoods.

The authors isolated three key factors that predicted risk of schizophrenia, namely, deprivation, population density, and economic inequality. Indicators of deprivation includes unemployment, low income, low education and high crime.

Dr Kirkbride said: “Our research adds to a wider and growing body of evidence that inequality seems to be important in affecting many health outcomes, now possibly including serious mental illness. Our data seems to suggest that both absolute and relative levels of deprivation predict the incidence of schizophrenia.

For some ethnic groups, psychosis risk was also related to the ethnicity of the neighbourhood. For example, for black African groups, there was a lower risk of psychotic illness where the neighbourhood had a high black African composition. Incidence rates of schizophrenia were higher for black Caribbean groups in communities that were ethnically segregated. These findings support the possibility that the socio-cultural composition of our environment could positively or negatively influence risk of schizophrenia and other similar disorders.

Dr Kirkbride highlighted the changing demographics of the boroughs that were investigated: “East London has changed substantially over recent years, not least because of the Olympic regeneration. It would be interesting to repeat this work in the region to see if the same patterns were found.

Our research suggests that more densely populated, more deprived and less equal communities experience higher rates of schizophrenia and other similar disorders. This is important because other research has shown that many health and social outcomes also tend to be optimal when societies are more equal.”

This work was funded by St Bartholomew’s & the Royal London Hospital Special Trustees; East London & the City Mental Health National Health Service Trust R&D; the Wellcome Trust; National Institute of Health Research Collaboration for Leadership in Applied Health Research and Care and National Institute of Health Research programme grants.